The laboratory core is designed to support the five projects by satisfying their needs for the biochemical and physiological measurements that identify their intermediate phenotypes. The wide range of assays provided are germane to salt-sensitive hypertension, the renin- angiotensin-aldosterone axis, the kinin system, assessment of the determinants of hypertension, renal perfusion and sodium homeostasis. All of the techniques and assays described in the core are in current use in the laboratories encompassed by the core, and the professional and laboratory active personnel already interact in filling their roles. The core structure results in cost savings through economy of scale and more efficient resource allocation, improves quality control and facilitates collaboration. Additional advantages include reduced turnaround time on assays and more efficient adaptation as new demands arise. We are fortunate in that the laboratory core in this program is not a construct invented for this proposal, but rather a current, active resource which will be able to function with far greater efficiency in the structure provided by the program. We are also fortunate that all of the collaborative arrangements described herein, once again, are not a construct invented for this proposal but rather reflect longstanding and ongoing relationships.